The tractor beam, which is a staple of science fiction like 'Star Wars' and 'Star Trek' that was used to grab spaceships and other things remotely, is going to enter the realm of reality. On Tuesday, researchers said that they have created a tractor beam that takes help from high-amplitude sound waves to levitate, move and rotate tiny objects without coming in touch with them.

The researchers have envisioned medical and other applications for the device. Study's lead author Asier Marzo of Britain's University of Bristol and Spain's Public University of Navarre said that being a mechanical wave, sound can exert large forces on objects. While giving an example, Marzo said that just recall once, the last time you were in a concert and your chest started vibrating with the music.

According to Marzo, this sonic tractor beam has manipulated objects up to nearly one-seventh of an inch (4 mm) in diameter and can influence and control the levitated objects' position and orientation. In the tractor beam, ultrasound at a frequency of 40 kilohertz is used, and people can hear just below 20 kilohertz.

During the study, the researchers took help of sound waves from 64 miniature loudspeakers, known as transducers, for creating what they called 'acoustic holograms' to control an object without making a contact with it. The waves get transformed into tweezers for lifting an object, a vortex for grabbing a levitating object in place and a cage for surrounding an object and seize it in place.

Researchers have now built a working tractor beam that uses high-amplitude sound waves to generate an acoustic hologram which can pick up and move small objects. Acoustic levitation itself isn't new. In fact, NASA has been using it since the '60s to create artificial gravity for experiments. But unlike previous uses of the technique, the new device doesn't have to completely surround its objects with speakers. Instead, 64 miniature loudspeakers at the base of the object are used to create high-pitched and high-intensity sound waves, surrounding the object with high intensity sound.

The paper and video both describe small plastic beads being controlled, so this is obviously not something that is going to be used to draw the Millennium Falcon into the Death Star any time soon. Not that the authors care: their current goal is “in vivo manipulation since the device could be applied directly onto the skin with the manipulation taking place inside the body; similar to an ultrasound scanner but for manipulating particles”.

Right now Marzo's invention is pretty limited in the size of what it can manipulate—mostly objects of plastic around the 1-millimeter size. Boosting the power output of his tiny transducers could allow the manipulation of even metal-dense objects. But, Marzo says, it may be more useful to work in the micro-range. The most immediate use of the tech—and what Marzo calls the simplest, even though it sounds like sci-fi—would be using many speakers to create complex, computer-generated sound paintings that levitate many small pellets in predetermined shapes.

Marzo said, "A simple wave will just push the particle in the direction of propagation. However, multiple waves will interfere with each other and create complex, acoustic 3D shapes that exert forces from all directions and keep the particle in place".